In our country, Japan, with its small land area, enhancing the efficiency and increasing the profitability of agriculture are an urgent problem to be solved.
The inventors have been studying fertigation as a promising method to enhance the efficiency and profitability of agriculture, and working on development of a system expected to highly realize the same.
Fertigation is a water-saving crop cultivation technique, which provides culture solution prepared by diluting fertilizer with an appropriate amount of water to crops being cultivated in soil by a required amount at a required time using an irrigation tube.
Patent Literature 1 is a prior art literature of a cultivation method of crops using fertigation, which seems to be partially related to the present invention. Patent Literature 1 has disclosed a method of cultivating crops by fertigation, the method including: (1) a unit configured to analyze soil and measure chlorine ion density and sulfate ion density in the soil, prior to cultivating crops; (2) a unit configured to acquire a contribution value (ds/m) of chlorine ions and sulfate ions to electrical conductivity; (3) a unit configured to determine a management target value for the electrical conductivity of soil solution by adding the contribution value acquired at above (2) to a standard electrical conductivity; (4) a unit configured to measure the electrical conductivity in the soil solution during a cultivation period; and (5) a unit configured to adjust the density and the amount of fertilization solution to be supplied when performing fertilization so that the electrical conductivity acquired at above (4) is maintained within the range of the management target value determined at above (3).